The chairman of Tasmania's Environment Protection Authority (EPA) will oversee a new investigation into the quality of St Helens drinking water.

Tests paid for by St Helens GP Alison Bleaney and marine ecologist Marcus Scammell show water in the George River contains toxins from plantation eucalyptus leaves.

EPA chairman John Ramsay will look for interstate and overseas scientists to look at the tests and water quality issues in the river.

The Director of Public Health Dr Roscoe Taylor expects the process to start in the next few days.

"First of all it's important that he lines up the necessary people and get some multi-party agreement on what that looks like, the process he wants, is it an advisory group or a reference group, who the scientists are," he said.

"There are needs for interstate or international scientists to be involved so that everyone owns that process and is willing to share the information freely and in a collaborative manner."

Dr Bleaney has welcomed scrutiny of her research.

She says while she is pleased public health is taking the matter seriously, the investigative panel needs to be independent.

"I think it has to be a completely independent investigation. It has to be staffed by people who are independent of the Tasmanian government," she said.

"It needs to be chaired by somebody who's completely impartial. Whether we like it or not, the EPA is part of the problem that's been going along here."

Dr Bleaney says Mr Ramsay is not the right person for the job.

The Tasmanian Greens are urging the Government to fully fund any investigation.

Greens leader Nick McKim says the investigation must be transparent because the issue is harming Tasmania's reputation.

"This issue is now damaging Tasmania's brand. It is putting at risk the significant investment in many small businesses in Tasmania's tourism industry," he said.

"It's time that Labor and the Liberals put their hands up and admitted responsibility for allowing rampant chemical use and rampant plantation establishment in Tasmania's water catchments."

Senator O'Brien told the Senate last night that what is needed is impartial scientific investigation.

"In the absence of that, and might I say in the run-up to a state election, one might be led to the view that the motives of those making the claims and going on national TV are less than those which they appear to be on the face of the statements that have been made."